Fuel system for oil burning engines



Oct. 6, 1936. c. CUMMINS FUEL SYSTEM FOR OIL BURNING ENGINES Filed Sept. 21, 1953 271/672 2%71' (Yeaazj (fizz/{inks Patented st. 6, 1936 UNITED STATES E NT r 2,056,259 I a FUEL SYSTEM son on. nmme ems Clessie L. Cummins, Columbus, Ind.,"-assignor to Oil Engine Development Company, C lum 11141., a corporation of Indiana v plication September 21, 1933. Serial masonic 3 Claims. (Cl. 158-364) My invention relates to fuel systems for oil burning engines and more particularly to that type in which provision is made for collecting for re-use leakage oil that may occur in the distributing system to the cylinder injectors.

The device of the present application is intended more especially for use in connection with, and as an improvement on, the fuel pump and distributing apparatus for internal combustion engines disclosed in my co-pending application, Serial No. 438,048, filed March 22, 1930, but the essential conception is also adaptable to other operating conditions. In the indicated apparatus, the oil is delivered under pressure to the several cylinder injectors and provision is made for collecting such leakage as may occur around each injector and in the region of the distributor by causing the same to gravitate to the bottom of the distributor housing, from which the leakage is pumped back to the main tank by a suitable gear pump. This method of handling the leakage occasionally caused a building up of pressure in the main tank.

It is accordingly one of the objects of my invention to devise a fuel system which is constructed and arranged to prevent any building up of pressure in the main tank by providing for a free drainage of the leakage into an auxiliary reservoir or fuel source, from which the oil may be again pumped into the injector lines.

A further object is to devise a fuel system having the foregoing characteristics in which a common chamber is provided between the main tank and the injector lines, fresh oil from the main tank being pumped through this chamber and the latter also receiving by gravity any leakage from the injectors.

A further object is to provide a fuel system of the type indicate having a float chamber which functions as an auxiliary fuel tank by receiving leakage which drains directly into the chamber and also'fresh fuel from the main tank, a pump being utilized to deliver the mixture of leakage and fresh oil to the injector lines.

These and further objects of my invention will be set forth in the following specification, reference being had to the accompanying drawing, and the novel means by which said objects are effectuated will be definitely pointed out in the accompanying claims.

In the drawing:

Figure 1 is a conventional end view of an oil burning engine showing my improved fuel system associated therewith.

Fig. 2 is an enlarged, vertical section of the lower portion of the distributorfhousin shown in ,Fig. 1, illustrating the manner of; driving the gear pumpsfor the system and their association with the auxiliary fuel chamben,

Fig. 3 is aldiagrammatic, sectional vie tain of the elementsof thefuel system, namely, the gear pump and the 1 float or ,aindliary ufuel chamber, these parts beingshown in :-displaced relation in order to more particularly, illustratetheir operative relation. ,1 s 4 Referring to the drawing-thenumeral ll designates a conventional type of oil burning, engine having a cylinder block I i, a crank case;.i 2 and a crank shaft i3. Adistributor-housingH s-:,con-

veniently mounted on thaengine; oneztype; of such mounting being illustrated and l described in the foregoing, copendingapplication;althQllBh it will be understood that other distributor. .ar-

rangements may be adopted without affectinggthe general scheme of my improved fuelsystem.

A shaft i5 is journaled in the housing It and may be driven by any suitable gearingpinot shown) from the crank shaft :i3.;-"A bevelsgear i6 is mounted on the shaft l5 and meshes withasecond bevel gear ll that isfixed upon one endof a shaft it that is journaledinga-pumpz casing I9 extending from the lower end of thedistributor housing M. The pump casing i9 is provided with pump chambers 20 and 2| which are separated from each other by a wall 22 and within which operates gear pumps, each composed of a pair of meshing gears 23 and 24, respectively. As clearly shown in Figs. 2 and 3 for each pump, the gears 23 and 24 are mounted upon the shaft it, while the other gears of each pump are mounted upon an offset shaft 25 that is also journaled in the pump casing l9.

The inlet side of the pump chamber 20 is connected by a pipe 26 to a main fuel tank 21, while the outlet end thereof is connected by a pipe 28 with a passage 29 leading into a fuel chamber 30. The delivery end of the passage 29 is operatively related to a needle valve 3| whose position is controlled by a ball float 32 suitably mounted for pivotal action in the chamber 30 under the influence of the fuel in the chamber. A pipe 35 connects the chamber 30 with the inlet side of the pump chamber 2! and a pipe 36 connects the outlet side of the last-noted chamber with the distributor represented generically by the numeral 31 in Fig. 1. This location of the distributor 'follows the design shown in my copending appli- According to the foregoing application, provision is made for returning to the distributor housing llanyleakagewhichmayoccuraroundthe injectors and pump units and this return is elected by means of a return pipe ll whose lower end delivers the leakage into the lower end of the casing M, from which it may pass by gravitythrough an opening 4! into the fuel chamber II.

In the operation of the fuel system, the fuel is pumped from the main tank 21 by the gear pump 23 into the float chamber "and from this chamber, the fuel is pumped by means of the gear pump 24 to the cylinder injectors'through the pipe 3|, distributor i1 and pipe 88. As before noted, any leakage which may occur around the injectors is returned to the float chamber 30 by means of gravity through the pipe ll. Similarly,

such leakage as may occur in the region ,of the distributor may also drain by gravity. into the chamber 80. I

The height of the fuel in the chamber 30 is limited by the needle valve 3| which insures that the fuel will not rise so high as to prevent a free 'drainage of theleakage fuel into the chamber 30, The principal advantage of my improved system is that the leakage fuel is returned to an auxiliary chamber under gravity, instead of being pumped directly back to the main tank and, further, that this leakage is conveniently associated with fresh fuel proceeding from the main tank.

When the needle valve ll reaches-a position which closes the passage 29, provision is made in the gear pump 23 for by-passing the fuel around the pump until the needle valve again opens. This result is achieved merely by providing a bypass I! which connects the chamber 20 on opposite sides of the pump and locating in this passage at some convenient point a spring-actuated ball check valve 34. A similar construction is provided for the gear pump 24, as shown in Fig. 3.

I claim:

1.The combination with an oil burning engine provided with an injector for forcing fuel into the engine cylinder and a main fuel supply tank, of means for feeding fuel from the tank-to the injector comprising a housing, a distributor mounted on the housing so that fuel leaking therefrom will drain into said housing, means for feeding fuel leakage from the injector to the housing, a fuel chamber mounted on the housing and having communication therewith to drain from the housing any fuel leakage fed thereto, means for feeding fuel from the supply tank to the fuel cham- 5 her, means for feeding fuel to the distributor from said chamber, and means for conducting fuel from the distributor to the injector.

2. The combination with an oil burning engine provided with an injector for feeding fuel into the 10 enginecylinder and a main fuel supply tank, of means for feeding fuel from the tank into the injector comprising a housing, a distributor mounted on the housing so that any fuel leaking therefrom will drain into said housing, means for 1 v feeding fuel leakage from the injector to the housing, a fuel chamber mounted on the housing and having communication therewith to drain the fuel chamber, a float valve for controlling feeding of fuel into said chamber by said pump, means for bypassing fuel around said pump when the float valve isclosed, means for feeding fuel to 25 the distributor from said chamber, and means for conducting fuel from the distributor to the inhousing, a pair of pump units supported on the housing so that leakage therefrom will be fed to the housing, a fuel chamber mounted on the housing and having communication therewith to drain, 40 from the'housing any fuel leakage fed thereto, means for causing one of said pumps to feed fuel from the supply tank to the fuel chamber, means for causing the second pump to feed fuel to the distributor from said chamber, and means for. 5 conducting fuel from the distributor to the injector.

' CLESSIE L. CUMMINS. 

